1. Field of the Invention
The present invention relates to an adjustable bed and, more particular, to a bed having an adjustable frame such that the height of the head and foot of the mattress can be easily and independently regulated without the necessity of powered equipment.
2. Description of the Background
Probably for as long as people have slept or reclined on furniture (hereinafter referred to as a bed), users have devised techniques for altering the bed to better accommodate their particular needs and/or wants. It is clear that U.S. patents to adjustable beds date back in excess of 100 years. U.S. Pat. No. 202,685 issued in 1878 discloses a "bed stead" which allowed angular adjustment of one portion of the upper planar canvas with respect to the position of another portion of the canvas. U.S. Pat. No. 327,699 issued in 1885 discloses a mechanism for adjusting the foot of a bed relative to its fixed elevation head.
Manufacturers of early versions of adjustable beds often employed the concept of a hand crank and gearing to adjust the position of the sleeping surface relative to the floor, and/or utilized a separate mattress frame apart from the bed frame. Both of these concepts are disclosed, for example, in U.S. Pat. No. 506,056, while U.S. Pat. Nos. 1,506,525 and 3,259,921 each disclose techniques for adjusting the head of the bed. U.S. Pat. No. 1,427,618 discloses a bed spring mounted for center pivotal movement, so that elevation of the head results in equal lowering of the foot of the bed.
Those skilled in the art have long appreciated that the public's acceptance and utilization of an adjustable bed is related to the cost of manufacturing the bed, the cost of maintaining the bed in an operational condition, and the reliability of the bed adjustment equipment. Substantially increased manufacturing cost are associated with providing a bed with one frame for the bed (comprising side rails and end rails), and a separate frame for the box spring and/or mattress. While limited adjustment of the bed is possible according to the teachings of U.S. Pat. Nos. 2,018,529, 2,527,111, 2,584,135, and 2,985,891, the complexity and cost of manufacturing beds according to those patents has certainly limited their acceptance in the marketplace. Most consumers do not envision their bed as being "adjustable" in height, except to the extent that nominal adjustment is achieved by the screw-type leveling pads threaded to the ends of the bed frame legs. Nevertheless, others continue to try to improve upon the concept of an adjustable bed having a separate bed frame and mattress frame, as evidenced by more recently issued U.S. Pat. Nos. 4,062,074 and 4,715,073.
Beds commonly employed by patients receiving medical treatment often include mechanisms for adjusting the bed. These "hospital-type" beds are, however, also generally considered complex, unattractive, and too expensive for use by individuals not requiring such medical attention. An adjustable hospital-type bed is disclosed in Canadian Patent No. 630,105, and U.S. Pat. Nos. 4,070,720 and 4,097,937 disclose hospital-type beds intended for hospital use and/or use at home by patients under the care of a physician. U.S. Pat. No. 3,305,876 discloses an adjustable bed intended for hospital and nursing facility use, and provides for vertical height adjustment but not independent adjustment of both the head and the foot of the bed.
Many prior art adjustable beds have functional limitations which have further limited there acceptance by the public. U.S. Pat. No. 3,761,970 discloses an adjustable bed carriage, although adjustment of both the head and the foot of the bed relative to the floor is not envisioned. U.S. Pat. No. 2,750,602 discloses a bed which allows for two levels of elevation, although again both head and foot adjustment is not disclosed. U.S. Pat. No. 3,802,002 teaches an adjustable bed with a hand crank mechanism for achieving vertical movement of the bed, although again vertical movement of the head of the bed relative to the foot of the bed is not envisioned. U.S. Pat. No. 2,939,157 discloses a bed frame with controlled movement cross rails.
Numerous other inventors have attempted to devise an adjustable bed which can be manufactured at a relatively low cost, does not distract from the appearance of the bed, and provides high flexibility to meet the desires of the consumer. In spite of such numerous attempts, inventors in recent years have continued to devise techniques for achieving adjustment of a bed. U.S. Pat. Nos. 4,118,811 and 4,354,287 each provide for some adjustment of a bed, but do not provide for independent adjustment of both the head and the foot of a bed. U.S. Pat. No. 4,101,990 teaches a mechanism for adjusting the height of the bed, but does not teach head and foot adjustment. U.S. Pat. No. 4,087,872 discloses a bed frame which includes an electrically powered device coupled to arms to adjust the height of the head and the foot of the bed independently, although the technique of moving the frame with respect to the stationary legs requires the use of special headboard and footboard posts, and accordingly has not satisified the desires of consumers.
In addition to the above-identified patents, various mechanisms have been devised for connecting the rails of a bed frame to a headboard and/or footboard. Exemplary of such mechanisms are U.S. Pat. Nos. 2,799,868, 3,188,664, 3,758,895, and 4,501,033. While the teachings of these patents provide mechanisms for achieving a mechanical connection between the headboard to the frame of the bed, they do not teach a mechanism for achieving truly vertical inclination of the headboard with respect to an inclined bed frame, so that the elevation of both the head and the foot of the bed can be easily controlled by the user while the headboard remains in a vertical plane.
The disadvantages of the prior art are overcome by the present invention, and improved techiques are hereinafter disclosed for manufacturing and using an adjustable bed which can be easily regulated by the user so that elevation of both the head and the foot of the bed can be separately controlled without complex mechanisms and/or expensive power driving devices. Moreover, the adjustable bed according to this invention includes the capability of having an inclined upper sleeping surface for a bed supported on a similarly inclined bed frame, while the headboard and/or footboard connected to the inclined bed frame remains within a vertical plane, and can be adjusted up and down within this vertical plane.